Thermal insulation

Abstract

The present invention relates Inorganic fibres having a composition comprising: 61.0 to 70.8 wt % SiO2; 27.0 to 38.9 wt % CaO; 0.10 to 2.0 wt % MgO; and optionally, an amount of other components providing a balance up to 100 wt %. A sum of SiO2 and CaO is greater than or equal to 97.8 wt % and wherein the amount of the other components, when present, comprise no more than 0.80 wt % Al2O3.

1 . Inorganic fibres having a composition comprising:
 61.0 to 70.8 wt % SiO 2 ;   27.0 to 38.9 wt % CaO;   0.10 to 2.0 wt % MgO; and   optionally, an amount of other components providing a balance up to 100 wt %, wherein a sum of SiO 2  and CaO is greater than or equal to 98.2 wt % and wherein the amount of the other components, when present, comprise no more than 0.67 wt % Al 2 O 3 .   
     
     
         2 . The inorganic fibres of  claim 1 , wherein the amount of MgO is configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100° C. for 24 hours, wherein any said surface crystallite grains have an average crystallite size of a range of from 0.0 to 0.90 μm. 
     
     
         3 . The inorganic fibres of  claim 1 , wherein the amount of other components is configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100° C. for 24 hours, wherein any said surface crystallite grains have an average crystallite size of a range of from 0.0 to 0.90 μm. 
     
     
         4 . The inorganic fibres of  claim 1 , wherein the amount of other components is configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100° C. for 24 hours, wherein any said surface crystallite grains have an average crystallite size of a range of from 0.0 to 0.60 μm. 
     
     
         5 . The inorganic fibres of  claim 1 , wherein SiO 2  is present in an amount configured to inhibit the reactivity of the inorganic fibres, such that the inorganic fibres are non-reactive with mullite when in contact at 1200° C. for 24 hours. 
     
     
         6 . The inorganic fibres of  claim 1 , wherein the composition comprises less than 69.6 wt % SiO 2 . 
     
     
         7 . The inorganic fibres of  claim 1 , wherein the composition comprises at least 28.5 wt % CaO. 
     
     
         8 . (canceled) 
     
     
         9 . The inorganic fibres of  claim 1 , wherein the sum of SiO 2  and CaO is greater than or equal to 98.4 wt %. 
     
     
         10 . The inorganic fibres of  claim 1 , wherein the sum of SiO 2  and CaO is greater than or equal to 98.6 wt %. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . The inorganic fibres of  claim 1 , wherein the other components comprise no more than 0.65 wt % Al 2 O 3 . 
     
     
         15 . The inorganic fibres of  claim 1 , wherein the other components comprise no more than 0-70.63 wt % Al 2 O 3 . 
     
     
         16 . The inorganic fibres of  claim 1 , wherein the other components comprise no more than 0.4 wt % alkaline metal oxides. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . The inorganic fibres of  claim 1 , wherein the other components account for at least 0.3 wt % of the composition of the inorganic fibres. 
     
     
         20 . The inorganic fibres of  claim 1 , wherein the other components comprises a range of from 0.1 to 1.4 wt % of the sum of BaO+Cr 2 O 3 +Fe 2 O 3 +HfO 2 +La 2 O 3 +Mn 3 O 4 +Na 2 O+K 2 O+P 2 O 5 +SrO+SnO 2 +TiO 2 +V 2 O 5 +ZrO 2 +ZnO. 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . The inorganic fibres of  claim 1 , wherein the other components comprises a range of from 0.1 to 0.8 wt % of the sum of BaO+Cr 2 O 3 +Fe 2 O 3 +HfO 2 +La 2 O 3 +Mn 3 O 4 +Na 2 O+K 2 O+P 2 O 5 +SrO+SnO 2 +TiO 2 +V 2 O 5 +ZrO 2 +ZnO. 
     
     
         24 . The inorganic fibres of  claim 1 , wherein the other components comprise no more than 1.2 wt % of the fibre composition. 
     
     
         25 . The inorganic fibres of  claim 1 , wherein the sum of SiO 2 , CaO and MgO is greater than or equal to 98.5 wt %. 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . The inorganic fibres of  claim 1 , wherein an amount of MgO and other components are configured to obtain a vacuum cast preform of the inorganic fibres having a shrinkage of 3.5% or less when exposed to 1300° C. for 24 hrs. 
     
     
         31 . The inorganic fibres of  claim 1 , wherein a vacuum cast preform of the inorganic fibre has a composition configured to obtain a shrinkage of 5.0 wt % or less when exposed to 1300° C. for 24 hours. 
     
     
         32 . (canceled) 
     
     
         33 . The inorganic fibres of  claim 1 , wherein the inorganic fibres are non-reactive with mullite when in contact at 1200° C. for 24 hours. 
     
     
         34 .- 54 . (canceled)